Jquery in endpoint

Sorry, I should've given some more detail. I understand the entire stand-alone nature. I had set the type of endpoint to text/javascript and then included it in the wrapper footer using a script tag, since I thought the Lithium jQuery would have loaded by then. The JS loads fine but when it tries to use $, I come across the error.

Here's the watered down code:

(function($){
	test = {
		url: "https://lithiumdev.domain.com/restapi/vc/search/messages", //used our real domain in the actual code

		getByLabel: function(labelName, callback){
			var data = { 
				q: "is_root:true AND labels:"+ labelName
			}

			$.post(test.url, data, callback);
		},
		displayMessageInfo: function(data){
			console.log(data);
		}
	}
})(LITHIUM.jQuery);

I call the function test.getByLabel('test',test.displayMessageInfo) and then the error happens: TypeError: Cannot call method 'post' of undefined'.

I may be thinking about this all wrong or it may be something dumb. But, anyways, thanks for the help!